void swap(int x, int y) {
    int temp;
    temp = x;
    x = y;
    y = temp;
    printf("In swap: %d %d\n", x, y);
}
 
int main() {
    int a = 10;
    int b = 20;
    swap(a, b);
    printf("After swap: %d %d\n", a, b);
    return 0;
}